The invention relates to a system for influencing the speed of a motor vehicle. Control systems of this kind are increasingly being used in motor vehicles, in particular upper and upper medium class private cars, under the name of ACC (Autonomous/Adaptive Cruise Control).
Devices are known which control the driving speed of a motor vehicle, wherein the driver can preset a desired speed and the driving speed of the motor vehicle is brought to this target speed by a speed controller and kept there all the time this device is activated. However, no monitoring of the driving speed of a motor vehicle traveling ahead takes place in this case. Therefore the driver has to intervene if his own motor vehicle comes too close to the motor vehicle traveling ahead. Similarly, if the speed of the motor vehicle traveling ahead increases, the driver can also increase the speed of his own vehicle correspondingly.
A device which removes from the driver the monitoring of the distance from the motor vehicle traveling ahead and adjusts the speed of his own motor vehicle to the speed of a motor vehicle traveling ahead is described, for example, in EP-A-0 612 641.
In order to give ACC systems of this kind broader use successfully, safe and reliable operation of these systems is required, which also results in greater driving comfort and therefore increased acceptance by drivers. The invention is concerned in particular with the problem of improving the selection of the target motor vehicle and thus of making the performance or driving behavior of the driver's motor vehicle more reliable.